Answer: 
Explanation:
Given
Cross-sectional area of wire 
Extension of wire 
Extension in a wire is given by

where, 

for same force, length and material

Divide (i) and (ii)

Answer:
0.906 N
Explanation:
Formula for magnetic force acting on current carrying cable:

Where I = 345A is the current in the wire, B =
is the magnetic magnitude generated by Earth. L = 46.9 m is the cable length.
is the angle between vector B and cable direction.


The answer is A. the fields lines never cross, if you bring another magnet near it, the lines work just compress
Answer:
Active—A volcano is active if it is erupting, or may erupt soon. ...
Dormant—A dormant volcano is one that may have erupted before, but it is no longer erupting. ...
Extinct—An extinct volcano is not erupting and will never erupt again.
Explanation:
Answer:
After 4 s of passing through the intersection, the train travels with 57.6 m/s
Solution:
As per the question:
Suppose the distance to the south of the crossing watching the east bound train be x = 70 m
Also, the east bound travels as a function of time and can be given as:
y(t) = 60t
Now,
To calculate the speed, z(t) of the train as it passes through the intersection:
Since, the road cross at right angles, thus by Pythagoras theorem:


Now, differentiate the above eqn w.r.t 't':


For t = 4 s:
